Energy

class pulser.backend.Energy(*, evaluation_times=None, tag_suffix=None, default_aggregation_method=AggregationMethod.MEAN)

Bases: Observable

Stores the energy of the system at the evaluation times.

The energy is calculated as the expectation value of the Hamiltonian, i.e. <φ(t)|H(t)|φ(t)>.

Parameters:

• evaluation_times (Sequence[float] | None, default: None) – The relative times at which to compute the energy. If left as None, uses the default_evaluation_times of the backend’s EmulationConfig.

• tag_suffix (str | None, default: None) – An optional suffix to append to the tag. Needed if multiple instances of the same observable are given to the same EmulationConfig.

• default_aggregation_method (AggregationMethod, default: <AggregationMethod.MEAN: 2>) – How to combine the values of this observable from multiple results.

Attributes

default_aggregation_method	How the values from multiple results are combined.
tag	Label for the observable, used to index the Results object.
uuid	A universal unique identifier for this instance.
evaluation_times

Methods

apply

Calculates the observable to store in the Results.

Signatures

apply(*, state, hamiltonian, **kwargs)

Calculates the observable to store in the Results.

Return type:

Any

property default_aggregation_method: AggregationMethod

How the values from multiple results are combined.

property tag: str

Label for the observable, used to index the Results object.

Within a Results instance, all computed observables must have different tags.

Returns:

The tag of the observable.

property uuid: UUID

A universal unique identifier for this instance.